Date: Fri, 31 Mar 2017 15:21:48 +0800
From: Zhenyu Wang <zhenyuw@linux.intel.com>
To: Jiri Slaby <jslaby@suse.cz>
Cc: linux-kernel@vger.kernel.org, Martin Liska <mliska@suse.cz>,
        Zhi Wang <zhi.a.wang@intel.com>,
        Daniel Vetter <daniel.vetter@intel.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        David Airlie <airlied@linux.ie>, intel-gvt-dev@lists.freedesktop.org,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: disable KASAN for handlers
Message-ID: <20170331072148.lbb7x6tj5egkpppm@zhen-hp.sh.intel.com>
Reply-To: Zhenyu Wang <zhenyuw@linux.intel.com>
References: <20170330094627.29460-1-jslaby@suse.cz>
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On 2017.03.30 11:46:27 +0200, Jiri Slaby wrote:
> Handlers are currently the only blocker to compile the kernel with gcc 7
> and KASAN+use-after-scope enabled:
> drivers/gpu/drm/i915/gvt/handlers.c:2200:1: error: the frame size of 4376=
0 bytes is larger than 2048 bytes [-Werror=3Dframe-larger-than=3D]
> drivers/gpu/drm/i915/gvt/handlers.c:2402:1: error: the frame size of 9400=
 bytes is larger than 2048 bytes [-Werror=3Dframe-larger-than=3D]
> drivers/gpu/drm/i915/gvt/handlers.c:2628:1: error: the frame size of 1125=
6 bytes is larger than 2048 bytes [-Werror=3Dframe-larger-than=3D]
>=20
> It is due to many expansions of MMIO_* macros in init_generic_mmio_info.
> INTEL_GVT_MMIO_OFFSET generates for each such line a __reg and an
> offset. There are too many for KASAN to keep up.
>=20
> So disable KASAN for this file.
>=20
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Cc: Martin Liska <mliska@suse.cz>
> Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
> Cc: Zhi Wang <zhi.a.wang@intel.com>
> Cc: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: intel-gvt-dev@lists.freedesktop.org
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> ---
>  drivers/gpu/drm/i915/gvt/Makefile | 2 ++
>  1 file changed, 2 insertions(+)
>=20
> diff --git a/drivers/gpu/drm/i915/gvt/Makefile b/drivers/gpu/drm/i915/gvt=
/Makefile
> index b123c20e2097..942f1849d194 100644
> --- a/drivers/gpu/drm/i915/gvt/Makefile
> +++ b/drivers/gpu/drm/i915/gvt/Makefile
> @@ -6,3 +6,5 @@ GVT_SOURCE :=3D gvt.o aperture_gm.o handlers.o vgpu.o tra=
ce_points.o firmware.o \
>  ccflags-y				+=3D -I$(src) -I$(src)/$(GVT_DIR) -Wall
>  i915-y					+=3D $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
>  obj-$(CONFIG_DRM_I915_GVT_KVMGT)	+=3D $(GVT_DIR)/kvmgt.o
> +
> +KASAN_SANITIZE_handlers.o :=3D n
> --=20
> 2.12.2
>=20

Applied this, we'd better cleanup legacy usage to current i915 mmio reg def=
ine. Thanks!

--=20
Open Source Technology Center, Intel ltd.

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